Answer
Similarities:
They are fundamental forces of nature.
They hold atoms together, in a sense. The strong force binds nucleons together, and the electromagnetic force binds electrons to the nucleus.
Differences:
The strong force is the strongest fundamental force, and is much stronger than the EM force.
The strong force is always attractive. The EM force can cause particles to either attract or to repel.
The strong force only is effective at short range (nuclear distances). The EM force is a long-range, inverse-square force.
The two\times forces operate between different particles.
Work Step by Step
Nuclear force range is only within 10$^{-15}$m.